Table of Content 4.1 Thermionic Emission and Cathode Ray 4.2 Carthode Ray Oscilloscope 4.3 Semiconductor 4.4 Semiconductor Diode 4.5 Trasistor 4.6 Logic Gate

# Thermionic Emission and Cathode Ray

The SPM Physics Workbook is developed under the One-School.net Free Books Project. The content of this book is strictly follow Malaysia SPM (Sijil Pelajaran Malaysia) syllabus. The aim of this project is to provide a complete electronic supplementary network for students to develop self-learning skills by breaking the spoon-feed rituals and to encourage them to compile educational information from the Internet.
1) What is thermionic emission?

 Thermionic emission is the process which a metal emits light when it is heated. Thermionic emission is the process which a metal emits electron when it is heated. Thermionic emission is the process of emitting electrons from a metal.

2) Which of the following is not the factor that affects the rate of thermionic emission?

 Temperature of the metal. Surface area of the metal. Conductivity of the metal. Coated material on the surface of the metal.

3) Which of the following is true about cathode ray?
1. Cathode ray is a form of electromagnetic wave.
2. Cathode ray can be deflected by a magnetic field.
3. Cathode ray is produced by bombarding high speed electrons towards a metal plate.
4. Cathode ray can cause ionising effect when it passes through air.

 I and II only I, III and IV II, III an IV only II and IV only

4) Figure above shows an image on the screen of a Maltese Cross Tube. If a bar magnet is brought close to the Maltese Cross Tube as shown in the figure. What will be the possible new position of the image?

 P Q R S

5) Figure above shows a moving charge particle is deflected in an electric field. The angle of deflection is affected by

1. The velocity of the charge particle.
2. The mass of the charge particle
3. The amount of charge carried by the charge particle
4. The strength of the magnetic field.
 III and IV only I and III only II, III and IV only I, II, III and IV

6) Which of the following diagram shows the correct movement of a cathode ray when it approaches a charged sphere?

 P Q R S